In industrial applications, such as tank farms, the source of fire fighting fluid is frequently water drawn from a lake or a moat or a tank or a pond or the like, even from the ocean, (such sources will be referred to herein generically as a reservoir.) The reservoir is contained frequently by or within man-made dikes. Typically, water is supplied through a pipe extending out of a lower portion of a dike, or by a pipe extending over a dike, the pipe usually having some valved outlet with fittings.
A reservoir typically provides water under some pressure for fire fighting purposes. However, in almost all circumstances, even though the water may flow from a reservoir under some natural pressure, a pump is utilized to supply the necessary gallonage of water to the fire fighting conduits at a constant, predictable, design pressure, such as 150 psi.
In the instant application the pump and the source of water are both assumed to be of large scale. For instance, they may be of a scale to supply 40,000 gallons of water per minute to a hazard. Pumps utilized in such applications (including pump combinations) should be capable of at least supplying 2000 gpm water at the requisite pressure.
It is usually desired to mix an additive, such as a foam concentrate, into the water that is in transit from a reservoir to a hazard to fight fire. Typically in these applications an around-the-pump system is used for this addition. Around-the-pump systems traditionally entail bringing to a reservoir/hazard area a tank or source of additive, such as a foam concentrate, as well as a pump suitable not only for pressuring the water but also specially fitted with an “around-the-pump” additive supply inlet. This around-the-pump additive supply inlet links to an additive source on a suction side of the pump. On the discharge side pump output is siphoned off and routed around the pump back to its suction side, picking up, in transit, an appropriately metered amount of additive. Usually a jet pump is employed to help extract the additive from the additive source and into the around-the-pump lines. Water rich with foam concentrate is in such manner delivered to the suction side of the pump.
Pumps designed to function in an around-the-pump system are designed with, or are modified to have, an inlet on their suction side to support an around-the-pump line. This is typically a 2½ inch line.
It would be advantageous, however, in an emergency to be able to utilize standard pumps for an around-the-pump system. Standard pumps, of the requisite size but not fitted with special around-the-pump inlets, could be more easily and quickly found and set up on location at an industrial facility than specially fitted pumps. A system utilizing standard pumps could avoid the cost and loss of time involved in having to bring to a hazard a pump specially fitted with a suction side inlet in order to be able to operate an around-the-pump system.
The instant invention teaches and discloses a novel system, including methods and apparatus, for establishing an around-the-pump supply of additive to water from a large reservoir using standard pumps. The novel system does not require finding a pump already fitted with an appropriate around-the-pump suction side inlet. In the instant invention fittings are used, which can be pre-installed or brought to the reservoir and hazard area, such that together with a source of additive and appropriate hoses or lines, they can establish an effective around-the-pump supply of additive to water drawn from a large reservoir using an appropriately sized standard pump.